CHAPTER 7-1 Cisco PIX Firewall and VPN Configuration Guide 78-15033-01 7 Site-to-Site VPN Configuration Examples A site-to-site VPN protects the network resources on your protected networks from unauthorized use by users on an unprotected network, such as the public Internet. The basic configuration for this type of implementation has been covered in Chapter 6, “Configuring IPSec and Certification Authorities.” This chapter provides examples of the following site-to-site VPN configurations: • Using Pre-Shared Keys, page 7-1 • Using PIX Firewall with a VeriSign CA, page 7-7 • Using PIX Firewall with an In-House CA, page 7-13 • Using an Encrypted Tunnel to Obtain Certificates, page 7-20 • Connecting to a Catalyst 6500 and Cisco 7600 Series IPSec VPN Services Module, page 7-25 • Manual Configuration with NAT, page 7-35 Note Throughout the examples in this chapter, the local PIX Firewall unit is identified as PIX Firewall 1 while the remote unit is identified as PIX Firewall 2. This designation makes it easier to clarify the configuration required for each. Using Pre-Shared Keys This section describes an example configuration for using pre-shared keys. It contains the following topics: • Scenario Description, page 7-1 • Configuring PIX Firewall 1 with VPN Tunneling, page 7-2 • Configuring PIX Firewall 2 for VPN Tunneling, page 7-5 Scenario Description In the example illustrated in Figure 7-1, the intranets use unregistered addresses and are connected over the public Internet by a site-to-site VPN. In this scenario, NAT is required for connections to the public Internet. However, NAT is not required for traffic between the two intranets, which can be transmitted using a VPN tunnel over the public Internet.
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Cisco PIX78-15033-01
C H A P T E R 7
Site-to-Site VPN Configuration Examples
A site-to-site VPN protects the network resources on your protected networks from unauthorized use by users on an unprotected network, such as the public Internet. The basic configuration for this type of implementation has been covered in Chapter 6, “Configuring IPSec and Certification Authorities.” This chapter provides examples of the following site-to-site VPN configurations:
• Using Pre-Shared Keys, page 7-1
• Using PIX Firewall with a VeriSign CA, page 7-7
• Using PIX Firewall with an In-House CA, page 7-13
• Using an Encrypted Tunnel to Obtain Certificates, page 7-20
• Connecting to a Catalyst 6500 and Cisco 7600 Series IPSec VPN Services Module, page 7-25
• Manual Configuration with NAT, page 7-35
Note Throughout the examples in this chapter, the local PIX Firewall unit is identified as PIX Firewall 1 while the remote unit is identified as PIX Firewall 2. This designation makes it easier to clarify the configuration required for each.
Using Pre-Shared KeysThis section describes an example configuration for using pre-shared keys. It contains the following topics:
• Scenario Description, page 7-1
• Configuring PIX Firewall 1 with VPN Tunneling, page 7-2
• Configuring PIX Firewall 2 for VPN Tunneling, page 7-5
Scenario DescriptionIn the example illustrated in Figure 7-1, the intranets use unregistered addresses and are connected over the public Internet by a site-to-site VPN. In this scenario, NAT is required for connections to the public Internet. However, NAT is not required for traffic between the two intranets, which can be transmitted using a VPN tunnel over the public Internet.
Note If you do not need to do VPN tunneling for intranet traffic, you can use this example without the access-list or the nat 0 access-list commands. These commands disable NAT for traffic that matches the access list criteria.
If you have a limited number of registered IP addresses and you cannot use PAT, you can configure PIX Firewall to use NAT for connections to the public Internet, but avoid NAT for traffic between the two intranets. This configuration might also be useful if you were replacing a direct, leased-line connection between two intranets.
Figure 7-1 VPN Tunnel Network
The configuration shown for this example uses an access list to exclude traffic between the two intranets from NAT. The configuration assigns a global pool of registered IP addresses for use by NAT for all other traffic. By excluding intranet traffic from NAT, you need fewer registered IP addresses.
Configuring PIX Firewall 1 with VPN TunnelingFollow these steps to configure PIX Firewall 1:
Note In Example 7-2, the following statements are not used when enabling NAT for all traffic:nat 0 access-list 80
access-list 80 permit ip 10.0.0.0 255.0.0.0 192.168.12.0 255.255.255.00
Using PIX Firewall with a VeriSign CAThis section provides configuration examples showing how to configure interoperability between two PIX Firewall units (PIX Firewall 1 and 2) for site-to-site VPN using the VeriSign CA server for device enrollment, certificate requests, and digital certificates for the IKE authentication. This section includes the following topics:
• Scenario Description, page 7-7
• Configuring PIX Firewall 1 with a VeriSign CA, page 7-8
• Configuring PIX Firewall 2 with a VeriSign CA, page 7-11
Scenario DescriptionThe two VPN peers in the configuration examples are shown to be configured to enroll with VeriSign at the IP address of 209.165.202.130 and to obtain their CA certificates from this CA server. VeriSign is a public CA that issues its CA-signed certificates over the Internet. Once each peer obtains its CA-signed certificate, tunnels can be established between the two VPN peers using digital certificates as the authentication method used during IKE authentication. The peers dynamically authenticate each other using the digital certificates.
Note VeriSign’s actual CA server address differs. The example CA server address is to be used for example purposes only.
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For the general procedures to configure the PIX Firewall for a CA, see “Using Certification Authorities” in Chapter 6, “Configuring IPSec and Certification Authorities.”
This section provides an example configuration for the specific network illustrated in Figure 7-2.
Figure 7-2 VPN Tunnel Network
Configuring PIX Firewall 1 with a VeriSign CAPerform the following steps to configure PIX Firewall 1 to use a public CA:
ca identity example.com 209.165.202.130ca configure example.com ca 2 20 crloptional
These commands are stored in the configuration. “2” is the retry period, “20” is the retry count, and the crloptional option disables CRL checking.
209.165.201.8outside
192.168.12.2
192.168.12.1inside
New York
Router Router
PIX Firewall 1
3335
3
209.165.200.229outside
209.165.201.7 209.165.200.228
10.0.0.2
10.0.0.1inside
San Jose
PIX Firewall 2
VeriSign CA Serverexample.com209.165.202.130
Internet
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Step 5 Authenticate the CA by obtaining its public key and its certificate:
ca authenticate example.com
This command is not stored in the configuration.
Step 6 Request signed certificates from your CA for your PIX Firewall’s RSA key pair. Before entering this command, contact your CA administrator because they will have to authenticate your PIX Firewall manually before granting its certificate.
ca enroll example.com abcdef
“abcdef” is a challenge password. This can be anything. This command is not stored in the configuration.
Step 7 Verify that the enrollment process was successful using the show ca certificate command:
show ca certificate
Step 8 Save keys and certificates, and the CA commands (except those indicated) in Flash memory:
ca save allwrite memory
Note Use the ca save all command any time you add, change, or delete ca commands in the configuration. This command is not stored in the configuration.
Step 9 Configure an IKE policy:
isakmp enable outsideisakmp policy 8 auth rsa-sig
Step 10 Create a partial access list:
access-list 90 permit ip 192.168.12.0 255.255.255.0 10.0.0.0 255.0.0.0
Step 11 Configure a transform set that defines how the traffic will be protected:
crypto map toSanJose 20 ipsec-isakmp crypto map toSanJose 20 match address 90crypto map toSanJose 20 set transform-set strongcrypto map toSanJose 20 set peer 209.165.200.229
Step 13 Apply the crypto map to the outside interface:
crypto map toSanJose interface outside
Step 14 Tell the PIX Firewall to implicitly permit IPSec traffic:
sysopt connection permit-ipsec
Example 7-3 lists the configuration for PIX Firewall 1. PIX Firewall default configuration values and certain CA commands are not displayed in configuration listings.
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Chapter 7 Site-to-Site VPN Configuration ExamplesUsing PIX Firewall with a VeriSign CA
Configuring PIX Firewall 2 with a VeriSign CA
Note The following steps are nearly the same as those in the previous section “Configuring PIX Firewall 1 with a VeriSign CA” for configuring PIX Firewall 2. The differences are in Steps 1 and 2, and Steps 11 to 13, which are specific for the PIX Firewall 2 in this example.
Perform the following steps to configure PIX Firewall 2 for using a VeriSign CA:
ca identity example.com 209.165.202.130ca configure example.com ca 2 20 crloptional
These commands are stored in the configuration. “2” is the retry period, “20” is the retry count, and the crloptional option disables CRL checking.
Step 5 Authenticate the CA by obtaining its public key and its certificate:
ca authenticate example.com
This command is not stored in the configuration.
Step 6 Request signed certificates from your CA for your PIX Firewall’s RSA key pair:
ca enroll example.com abcdef
Before entering this command, contact your CA administrator because they will have to authenticate your PIX Firewall manually before granting its certificate.
“abcdef” is a challenge password. This can be anything. This command is not stored in the configuration.
Step 7 Verify that the enrollment process was successful using the following command:
show ca certificate
Step 8 Save keys and certificates, and the CA commands (except those indicated) in Flash memory:
ca save allwrite memory
Note Use the ca save all command any time you add, change, or delete ca commands in the configuration. This command is not stored in the configuration.
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Step 9 Configure an IKE policy:
isakmp enable outsideisakmp policy 8 auth rsa-sig
Step 10 Create a partial access list:
access-list 80 permit ip 10.0.0.0 255.0.0.0 192.168.12.0 255.255.255.0
Step 11 Configure a transform set that defines how the traffic will be protected:
crypto map newyork 10 ipsec-isakmp crypto map newyork 10 match address 80crypto map newyork 10 set transform-set strongcrypto map newyork 10 set peer 209.165.201.8
Step 13 Apply the crypto map to the outside interface:
crypto map newyork interface outside
Step 14 Tell the PIX Firewall to implicitly permit IPSec traffic:
sysopt connection permit-ipsec
Example 7-4 lists the configuration for PIX Firewall 2. PIX Firewall default configuration values and certain CA commands are not displayed in a configuration listing.
Using PIX Firewall with an In-House CAFor the general procedures to configure the PIX Firewall for a CA, see “Using Certification Authorities” in Chapter 6, “Configuring IPSec and Certification Authorities.” This section provides a specific example for the network illustrated in Figure 7-3 and includes the following topics:
• Scenario Description, page 7-14
• Configuring PIX Firewall 1 for an In-House CA, page 7-15
• Configuring PIX Firewall 2 for an In-House CA, page 7-18
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Scenario DescriptionPIX Firewall supports the use of the following certification authorities (CAs):
• VeriSign support is provided through the VeriSign Private Certificate Services (PCS) and the OnSite service, which lets you establish an in-house CA system for issuing digital certificates.
• Entrust, Entrust VPN Connector, version 4.1 (build 4.1.0.337) or higher. The Entrust CA server is an in-house CA server solution.
• Baltimore Technologies, UniCERT Certificate Management System, version 3.1.2 or higher. The Baltimore CA server is an in-house CA server solution.
• Microsoft Windows 2000, specifically the Windows 2000 Advanced Server, version 5.00.2195 or higher. The Windows 2000 CA server is an in-house CA server solution.
These are all in-house CA servers, except for VeriSign, which provides both a public CA and a private CA solution.
Note The example CA server address is to be used for example purposes only.
The in-house CA server in the following example is placed within the DMZ network of one PIX Firewall network (PIX Firewall 1). The VPN peer, PIX Firewall 2, should enroll and obtain its CA-signed certificates from the CA server residing within the network of PIX Firewall 1. PIX Firewall 2’s enrollment and certificate request process is accomplished through the Internet.
The two VPN peers in the configuration examples are shown to be configured to enroll with and obtain their CA-signed certificates from the Entrust CA server. PIX Firewall 1 will obtain its certificate from the CA’s local IP address of 10.1.0.2. PIX Firewall 2 will obtain its certificate from the CA’s global IP address of 209.165.202.131. After each peer obtains its CA-signed certificate, tunnels can be established between the two VPN peers. The peers dynamically authenticate each other using the digital certificates.
Figure 7-3 VPN Tunnel Network
209.165.201.8outside
192.168.12.1inside
DMZ10.1.0.1
Router Router
PIX Firewall 144
317
209.165.200.229outside
209.165.201.7 209.165.200.228
10.0.0.2192.168.12.2
San JoseNew York
10.0.0.1inside
PIX Firewall 2
Internet
In-houseCA Server10.1.0.2
(global address=209.165.202.131)
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Chapter 7 Site-to-Site VPN Configuration ExamplesUsing PIX Firewall with an In-House CA
Configuring PIX Firewall 1 for an In-House CAFollow these steps to configure PIX Firewall 1 for use with an in-house CA. These steps are similar to the procedure shown in “Using PIX Firewall with a VeriSign CA.”
Step 1 Define a host name:
hostname NewYork
Step 2 Define the domain name:
domain-name example.com
Step 3 Generate the PIX Firewall RSA key pair:
ca generate rsa key 512
This command is entered at the command line and does not get stored in the configuration.
Step 4 Define CA-related enrollment commands:
ca identity abcd 10.1.0.2 10.1.0.2ca configure abcd ra 2 20 crloptional
These commands are stored in the configuration. 2 is the retry period, 20 is the retry count, and the crloptional option disables CRL checking.
Note For a Microsoft CA server, specify the internal network address followed by a colon and the pathname to the server executable, such as 10.1.0.2:/CERTSRV/mscep/mscep.dll.
Step 5 Authenticate the CA by obtaining its public key and its certificate:
ca authenticate abcd
This command is entered at the command line and does not get stored in the configuration.
Step 6 Request signed certificates from your CA for your PIX Firewall’s RSA key pair:
ca enroll abcd cisco
Before entering this command, contact your CA administrator because they will have to authenticate your PIX Firewall manually before granting its certificate.
“cisco” is a challenge password. This can be anything. This command is entered at the command line and does not get stored in the configuration.
Step 7 Verify that the enrollment process was successful using the show ca certificate command:
show ca certificate
Step 8 Save keys and certificates, and the CA commands (except those indicated) in Flash memory:
ca save allwrite memory
Note Use the ca save all command any time you add, change, or delete ca commands in the configuration. This command is not stored in the configuration.
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Step 9 Map a local IP address to a global IP address:
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Configuring PIX Firewall 2 for an In-House CAFollow these steps to configure PIX Firewall 2:
Step 1 Define a host name:
hostname SanJose
Step 2 Define the domain name:
domain-name example.com
Step 3 Configure an IKE policy:
isakmp enable outsideisakmp policy 8 auth rsa-sig
Step 4 Define CA-related enrollment commands:
ca identity abcd 209.165.202.131 209.165.202.131ca configure abcd ra 2 20 crloptional
These commands are stored in the configuration. 2 is the retry period, 20 is the retry count, and the crloptional option disables CRL checking.
Note For a Microsoft CA server, specify the external (global) network address followed by a colon and the pathname to the server executable, such as 209.165.202.131:/certserv/mscep/mscep.dll.
Step 5 Generate the PIX Firewall RSA key pair:
ca generate rsa key 512
This command is entered at the command line and does not get stored in the configuration.
Step 6 Get the public key and the certificate of the CA server:
ca authenticate abcd
This command is entered at the command line and does not get stored in the configuration.
Step 7 Contact your CA administrator and send your certificate request:
ca enroll abcd cisco
“cisco” is a challenge password. This can be anything. This command is entered at the command line and does not get stored in the configuration.
Step 9 Save keys and certificates, and the CA commands (except those indicated) in Flash memory:
ca save allwrite memory
Note Use the ca save all command any time you add, change, or delete ca commands in the configuration. This command is not stored in the configuration.
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Step 10 Create a partial access list:
access-list 80 permit ip 10.0.0.0 255.0.0.0 192.168.12.0 255.255.255.0
Step 11 Define a crypto map:
crypto map newyork 20 ipsec-isakmp crypto map newyork 20 match address 80crypto map newyork 20 set transform-set strongcrypto map newyork 20 set peer 209.165.201.8
Step 12 Apply the crypto map to the outside interface:
crypto map newyork interface outside
Step 13 Tell the PIX Firewall to implicitly permit IPSec traffic:
sysopt connection permit-ipsec
Example 7-6 lists the configuration for PIX Firewall 2.
Example 7-6 PIX Firewall 2 VPN Tunnel Configuration
Using an Encrypted Tunnel to Obtain CertificatesThis section shows an example of how to perform CA enrollment and certificate requests via a site-to-site VPN tunnel between two PIX Firewall units (PIX Firewall 1 and 2). In the example, both PIX Firewall units enroll and request certificates from a CA server protected by PIX Firewall 1. PIX Firewall 2 enrolls and requests its certificate using an encrypted tunnel.
To accomplish this, you first establish a tunnel between the PIX Firewalls using a pre-shared key. You then use this tunnel to enroll and request the certificate for PIX Firewall 2. After obtaining a certificate, clear the IKE and IPSec SAs on both units and then configure them to use digital certificates.
Note The example CA server address is to be used for example purposes only.
This section includes the following topics:
• Establishing a Tunnel Using a Pre-Shared Key, page 7-21
• Establishing a Tunnel with a Certificate, page 7-24
This example uses the network diagram shown in Figure 7-4.
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Figure 7-4 VPN Tunnel Network
Establishing a Tunnel Using a Pre-Shared KeyThis section describes how to establish a tunnel using a pre-shared key. It includes the following topics:
crypto map toSanJose 20 ipsec-isakmp crypto map toSanJose 20 match address 90crypto map toSanJose 20 set transform-set strongcrypto map toSanJose 20 set peer 209.165.200.229
Step 8 Apply the crypto map to the outside interface:
crypto map toSanJose interface outside
Step 9 Tell the PIX Firewall to implicitly permit IPSec traffic:
sysopt connection permit-ipsec
Step 10 Generate the PIX Firewall RSA key pair:
ca generate rsa key 512
This command is entered at the command line and does not get stored in the configuration.
Step 11 Define CA-related enrollment commands:
ca identity abcd 10.1.0.2:/certsrv/mscep/mscep.dllca configure abcd ra 1 20 crloptional
These commands are stored in the configuration.
Note The ca identity command shown is specific to the Microsoft CA. The ca identity you use depends on the CA you are using.
Step 12 Get the public key and the certificate of the CA server:
ca authenticate abcd
This command is entered at the command line and does not get stored in the configuration.
Step 13 Contact your CA administrator and send your certificate request:
ca enroll abcd cisco
The string “cisco” is a challenge password. This can be anything. This command is entered at the command line and does not get stored in the configuration.
Step 14 Save keys and certificates, and the ca commands (except those indicated) in Flash memory:
ca save allwrite memory
Note Use the ca save all command any time you add, change, or delete ca commands in the configuration. This command is not stored in the configuration.
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crypto map newyork 20 ipsec-isakmp crypto map newyork 20 match address 80crypto map newyork 20 set transform-set strongcrypto map newyork 20 set peer 209.165.201.8
Step 8 Apply the crypto map to the outside interface:
crypto map newyork interface outside
Step 9 Tell the PIX Firewall to implicitly permit IPSec traffic:
sysopt connection permit-ipsec
Step 10 Generate the PIX Firewall RSA key pair:
ca generate rsa key 512
This command is entered at the command line and does not get stored in the configuration.
Step 11 Define CA-related enrollment commands:
ca identity abcd 10.1.0.2:/certsrv/mscep/mscep.dllca configure abcd ra 1 20 crloptional
These commands are stored in the configuration.
Note The ca identity command shown is specific to the Microsoft CA. The ca identity you use depends on the CA you are using.
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Step 12 Authenticate the CA by obtaining its public key and its certificate:
ca authenticate abcd
This command is entered at the command line and does not get stored in the configuration.
Step 13 Request signed certificates from your CA for your PIX Firewall’s RSA key pair. Before entering this command, contact your CA administrator because they will have to authenticate your PIX Firewall manually before granting its certificate:
ca enroll abcd cisco
“cisco” is a challenge password. This can be anything. This command is entered at the command line and does not get stored in the configuration.
Step 14 Save keys and certificates, and the CA commands (except those indicated) in Flash memory:
ca save allwrite memory
Note Use the ca save all command any time you add, change, or delete ca commands in the configuration. This command is not stored in the configuration.
Establishing a Tunnel with a CertificateThis section describes how to clear the SAs on each PIX Firewall and to establish a tunnel using a certificate. It includes the following topics:
• PIX Firewall 1 Configuration, page 7-24
• PIX Firewall 2 Configuration, page 7-25
PIX Firewall 1 Configuration
Follow these steps to configure PIX Firewall 1:
Step 1 Clear the IPSec SAs:
clear ipsec sa
Step 2 Clear the ISAKMP SAs:
clear isakmp sa
Step 3 Create a partial access list:
access-list 90 permit ip 192.168.12.0 255.255.255.0 10.0.0.0 255.0.0.0
Step 4 Configure NAT 0:
nat (inside) 0 access-list 90
Step 5 Specify the authentication method of rsa-signatures for the IKE policy:
isakmp policy 8 auth rsa-sig
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PIX Firewall 2 Configuration
Follow these steps to configure PIX Firewall 2:
Step 1 Clear the IPSec SAs:
clear ipsec sa
Step 2 Clear the ISAKMP SAs:
clear isakmp sa
Step 3 Create a partial access list:
access-list 80 permit ip 10.0.0.0 255.0.0.0 192.168.12.0 255.255.255.0
Step 4 Specify the authentication method of rsa-signatures for the IKE policy:
isakmp policy 8 auth rsa-sig
Connecting to a Catalyst 6500 and Cisco 7600 Series IPSec VPN Services Module
This section describes how to create an IPSec site-to-site tunnel between a Cisco Catalyst 6500 series switch with the Catalyst 6500 and Cisco 7600 Series IPSec VPN Services Module (VPNSM) and a PIX Firewall. It includes the following topics:
• Scenario Description, page 7-25
• Configuring IPSec Using a Trunk Port, page 7-26
• Configuring IPSec Using a Routed Port, page 7-30
• Verifying Your Configuration, page 7-35
Scenario DescriptionFigure 7-5 illustrates the network setup used in this example configuration.
Figure 7-5 VPN Tunnel Between PIX Firewall and Catalyst 6500 with VPNSM
The VPNSM has two Gigabit Ethernet (GE) ports with no externally visible connectors. These ports are addressable for configuration purposes only. Port 1 is always the inside port. This port handles all traffic from and to the inside network. The second port (port 2) handles all traffic from and to the WAN or outside networks. These two ports are always configured in 802.1q trunking mode.
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Packets are processed by a pair of VLANs, one Layer 3 (L3) inside VLAN and one Layer 2 (L2) outside VLAN. The packets are routed to the inside VLAN. After encrypting the packets the VPNSM uses the corresponding outside VLAN. In the decryption process, the packets from the outside to the inside are bridged to the VPNSM using the outside VLAN. After the VPNSM decrypts the packet and maps the VLAN to the corresponding inside VLAN, EARL routes the packet to the appropriate LAN port. The L3 inside VLAN and the L2 VLANs are joined together by issuing the crypto connect vlan command. There are three types of ports in the Catalyst 6500 series switches:
• Routed Ports—By default all Ethernet ports are routed ports. These ports have a hidden VLAN associated with them.
• Access Ports—These ports have an external or VLAN Trunking Protocol (VTP) VLAN associated with them. You can associate more than one port to a defined VLAN.
• Trunk Ports—These ports carry many external or VTP VLANs, on which all packets are encapsulated with an 802.1q header.
Configuring IPSec Using a Trunk PortPerform the following steps to configure an IPSec tunnel using the Catalyst 6500 trunk port configuration:
Step 1 Add the inside VLANs to the inside port of the VPNSM. Assuming that the VPNSM is on slot 3, use VLAN 100 as the inside VLAN and VLAN 200 as the outside, and configure the GE ports on the VPNSM as follows.
Step 8 Apply the crypto map to the VLAN 100 interface:
interface vlan100crypto map cisco
Example 7-7 shows the complete configuration for the VPNSM.
Example 7-7 VPNSM Configuration
!--- Define Phase 1 policy. crypto isakmp policy 1hash md5authentication pre-sharegroup 2crypto isakmp key cisco address 209.165.200.225!!!--- Define the encryption policy for this setup. crypto ipsec transform-set cisco ESP-Des esp-md5-hmac!!--- Define a static crypto map entry for the peer !--- with mode ipsec-isakmp. !--- This indicates that Internet Key Exchange (IKE) !--- will be used to establish the IPSec !--- Security Associations (SAs) for protecting the traffic !--- specified by this crypto map entry. crypto map cisco 10 ipsec-isakmpset peer 209.165.200.225set transform-set ciscomatch address 100!!no spanning-tree vlan 100!!!interface GigabitEthernet1/1no ip addressshutdownsnmp trap link-statusswitchport
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!interface GigabitEthernet1/2no ip addressshutdown!interface FastEthernet2/1ip address 10.10.10.1 255.255.255.0no keepalive!!--- This is the secure port which is configured in routed port mode. !--- This routed port mode purposely does not have an L3 IP address !--- configured, which is normal for the BITW process. !--- The IP address was moved from this interface to the VLAN 100 to!--- accomplish BITW, thereby bringing the VPN Services Module into!--- the packet path. This will be the L2 port VLAN on which the!--- VPN Services Module's outside port also belongs. interface FastEthernet2/2no ip addresssnmp trap link-statusswitchportswitchport access vlan 200switchport mode accesscrypto connect vlan 100!interface GigabitEthernet3/1no ip addresssnmp trap link-statusswitchportswitchport trunk encapsulation dot1q!--- VLAN 100 is defined as the Interface VLAN (IVLAN).switchport trunk allowed vlan 1,100,1002-1005switchport mode trunkflowcontrol receive oncdp enable!interface GigabitEthernet3/2no ip addresssnmp trap link-statusswitchportswitchport trunk encapsulation dot1q!--- The Port VLAN (PVLAN) configuration is handled by the VPN Services Module!--- transparently without user configuration!--- or involvement. It also is not shown in the configuration.!--- Note that for every IVLAN a corresponding PVLAN exists. switchport trunk allowed vlan 1,200,1002-1005switchport mode trunkflowcontrol receive oncdp enable!interface Vlan1no ip addressshutdown!!--- This is the IVLAN configured for intercepting the traffic !--- destined to the secure port on which the VPN Services Module's inside port !--- is the only port present. Interface Vlan100ip address 209.165.201.1 255.255.255.0crypto map cisco!interface Vlan200no ip address!
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ip classless!--- Configure the routing so that the device!--- knows how to reach its destination network. ip route 0.0.0.0 0.0.0.0 172.18.124.1!!--- This is the crypto ACL. access-list 100 permit ip 10.10.10.0 0.0.0.255 10.20.20.0 0.0.0.255
Example 7-8 shows the complete configuration for the PIX Firewall.
Configuring IPSec Using a Routed PortPerform the following steps to configure IPSec using the routed port configuration on the Catalyst 6500 VPN Services Module.
Step 1 Add the inside VLANs to the inside port of the VPNSM. Assuming that the VPNSM is on slot 3, use VLAN 100 as the inside VLAN and VLAN 200 as the outside, and configure the GE ports on the VPNSM as follows.
interface GigabitEthernet3/1 no ip address switchport switchport trunk encapsulation dot1q switchport trunk allowed vlan 1,100,1002-1005 switchport mode trunk
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Create your crypto map statement.crypto map cisco 10 ipsec-isakmp set peer 209.165.200.225 set transform-set cisco match address 100
Step 7 Apply the crypto map to the VLAN 100 interface:
interface vlan100crypto map cisco
Example 7-9 shows the complete configuration for the VPNSM.
Example 7-9 Catalyst 6500 Configuration
!--- Define Phase 1 policy. crypto isakmp policy 1hash md5authentication pre-sharegroup 2crypto isakmp key cisco address 209.165.200.225!!!--- Define the encryption policy for this setup. crypto ipsec transform-set cisco ESP-Des esp-md5-hmac
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!!--- Define a static crypto map entry for the peer !--- with mode ipsec-isakmp. This indicates that IKE !--- will be used to establish the IPSec !--- SAs for protecting the traffic !--- specified by this crypto map entry.
crypto map cisco 10 ipsec-isakmpset peer 209.165.200.225set transform-set ciscomatch address 100!!no spanning-tree vlan 100!!!interface GigabitEthernet1/1no ip addressshutdownsnmp trap link-statusswitchport!interface GigabitEthernet1/2no ip addressshutdown!interface FastEthernet2/1ip address 10.10.10.1 255.255.255.0no keepalive!!--- This is the secure port which is configured in routed port mode. !--- This routed port mode does not have an L3 IP address !--- configured, which is normal for the BITW process. !--- The IP address was moved from this interface to the VLAN 100 to!--- accomplish BITW, thereby bringing the VPN Services Module into!--- the packet path. This will be the L2 port VLAN on which the!--- VPN Services Module's outside port also belongs.Interface FastEthernet2/2no ip addresscrypto connect vlan 100!interface GigabitEthernet3/1no ip addresssnmp trap link-statusswitchportswitchport trunk encapsulation dot1q!--- VLAN 100 is defined as the IVLAN.switchport trunk allowed vlan 1,100,1002-1005switchport mode trunkflowcontrol receive oncdp enable!interface GigabitEthernet3/2no ip addresssnmp trap link-statusswitchportswitchport trunk encapsulation dot1q!--- The PVLAN configuration is handled by the VPN Services Module!--- transparently without user configuration!--- or involvement. It also is not shown in the configuration.!--- Note that for every IVLAN a corresponding PVLAN exists. switchport trunk allowed vlan 1,200,1002-1005switchport mode trunk
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flowcontrol receive oncdp enable!interface Vlan1no ip addressshutdown!!--- This is the IVLAN configured for intercepting the traffic !--- destined to the secure port on which the VPN Services Module's inside port !--- is the only port present. Interface Vlan100ip address 209.165.201.1 255.255.255.0crypto map cisco!interface Vlan200no ip address!ip classless!--- Configure the routing so that the device!--- knows how to reach its destination network. ip route 0.0.0.0 0.0.0.0 172.18.124.1ip route 10.20.20.0 255.255.255.0 209.165.200.225!!--- This is the crypto ACL.Access-list 100 permit ip 10.10.10.0 0.0.0.255 10.20.20.0 0.0.0.255
Example 7-10 shows the complete configuration for the PIX Firewall.
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Verifying Your ConfigurationYou can use the following commands to confirm that your configuration is working properly.
To display the settings used by the current IPSec SAs, enter the following command:
show crypto ipsec sa
To display all the current IKE SAs at a peer, enter the following command:
show crypto isakmp sa
To display the VLAN associated with the crypto configuration, enter the following command:
show crypto vlan
To display the VPNSM statistics, enter the following command:
show crypto eli
Manual Configuration with NATIn this example, two PIX Firewall units are used to create a Virtual Private Network (VPN) between the networks on each PIX Firewall unit’s inside interface. This section includes the following topics:
• PIX Firewall 1 Configuration, page 35
• PIX Firewall 2 Configuration, page 7-37
This network is part of an intranet. In this example, the VPN is created without the use of IKE or a CA and pre-shared keys are used.
PIX Firewall 1 ConfigurationFollow these steps to program the PIX Firewall 1 unit for IPSec:
Step 1 Create a crypto map command statement.
Step 2 Create the access-list command entries to select traffic for this policy.
Note For manual keying, only one access-list permit command statement is permitted in the configuration.
Step 3 Create the transform set for the crypto command statement entry.
Step 4 Define cryptographic state informations. These include SPI, and the necessary keys for manual keying and policy negotiation for ISAKMP.
Step 5 Repeat Steps 1-4 for each group of policies.
Step 6 Associate the crypto map command statement with an interface.
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Example 7-11 lists the configuration for PIX Firewall 1.
Example 7-11 Two Interfaces with IPSec—PIX Firewall 1 Configuration